#include "Head.cpp"

const int N = 10007;

int n, m;

struct Point{
    int x,y;
    bool operator < (const Point &com) const{
        if(y != com.y) return y < com.y;
        return x < com.x;
    }
}a[N];

int cost[N][N];
int f[N][N];

Point sta[407],tmp[407];
int top;
inline int cross(Point a,Point b,Point c){
    return (a.x - c.x) * (b.y - c.y) - (a.y - c.y) * (b.x - c.x);
}
inline int Graham(Point *a, int n){
    sort(a, a + n);
    sta[0] = a[0], sta[1] = a[1];
    top = 1;
    R(i, 0, n - 1){
        while(top && cross(sta[top], a[i], sta[top - 1]) >= 0) --top;
        sta[++top] = a[i];
    }
    int mid = top;
    nR(i,n - 2, 0){
        while(top > mid && cross(sta[top], a[i], sta[top - 1]) >= 0) --top;
        sta[++top] = a[i];
    }
    return top;

}
int Calc(Point a,Point b) {
    return abs((a.x + b.x) * (a.y+b.y)) % m;
}

int main(){
    FileOpen();

    while(scanf("%d%d", &n, &m) != EOF) {
        R(i,0, n - 1){
            io >> a[i].x >> a[i].y;
        }

        int tot = Graham(a,n);

        if(tot < n) {
            printf("I can't cut.\n");
            continue;
        }

        Fill(cost, 0);
        R(i,0,n - 1)
            R(j,i + 2, n - 1){
                cost[i][j] = cost[j][i] = Calc(sta[i], sta[j]);
            }

        R(i,0, n - 1){
            R(j,0, n - 1){
                f[i][j] = 0x7fffffff;
            }
            f[i][(i + 1) % n] = 0;
        }
        nR(i,n-3,0)
            R(j,i + 2, n -1)
                R(k, i + 1, j - 1){
                    f[i][j] = Min(f[i][j], f[i][k] + f[k][j] + cost[i][k] + cost[k][j]);
                }

        printf("%d\n", f[0][n-1]);
    }

    return 0;
}

段错误什么鬼

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Abs(a) ((a) < 0 ? -(a) : (a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long

#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt","r",stdin);

#else

#define D_e_Line ;
#define D_e(x)  ;
#define Pause() ;
#define FileOpen() ;

#endif

struct ios{
    template<typename ATP>ios& operator >> (ATP &x){
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    }
}io;
using namespace std;

const int N = 10007;

int n, m;

struct Point{
    int x,y;
    bool operator < (const Point &com) const{
        if(y != com.y) return y < com.y;
        return x < com.x;
    }
}a[N];

int cost[N][N];
int f[N][N];

Point sta[407],tmp[407];
int top;
inline int cross(Point a,Point b,Point c){
    return (a.x - c.x) * (b.y - c.y) - (a.y - c.y) * (b.x - c.x);
}
inline int Graham(Point *a, int n){
    sort(a + 1, a + n + 1);
    sta[0] = a[1], sta[1] = a[2];
    top = 1;
    R(i, 1, n){
        while(top && cross(sta[top], a[i], sta[top - 1]) >= 0) --top;
        sta[++top] = a[i];
    }
    int mid = top;
    nR(i,n - 1, 1){
        while(top > mid && cross(sta[top], a[i], sta[top - 1]) >= 0) --top;
        sta[++top] = a[i];
    }
    return top;

}
int Calc(Point a,Point b) {
    return abs((a.x + b.x) * (a.y+b.y)) % m;
}

int main(){
//FileOpen();

    while(scanf("%d%d", &n, &m) != EOF) {
        R(i,1,n){
            io >> a[i].x >> a[i].y;
        }

        int tot = Graham(a, n);

        if(tot < n) {
            printf("I can't cut.\n");
            continue;
        }

        Fill(cost, 0);

        R(i,1,n)
            R(j,i + 2, n){
                cost[i][j] = cost[j][i] = Calc(sta[i], sta[j]);
            }

        R(i,1,n){
            R(j,1,n){
                f[i][j] = 0x3f3f3f3f;
            }
            f[i][i % n + 1] = 0;
        }
        nR(i,n - 2,1){
            R(j,i + 2, n){
                R(k, i + 1, j - 1){
                    f[i][j] = Min(f[i][j], f[i][k] + f[k][j] + cost[i][k] + cost[k][j]);
                }
            }
        }

        printf("%d\n", f[1][n]);
    }

    return 0;
}