int minPathSum(vector<vector<int> > &grid) {

int n = grid.size();

if (n == 0) return 0;

int m = grid[0].size();

vector<vector<int> >f(n+1,vector<int>(m+1,INT_MAX));

for(int i = 1; i <= n; i++){

for(int j = 1; j <= m; j++){

if(i == 1 && j == 1)

f[i][j] = grid[i-1][j-1];

else {

f[i][j] = min(f[i-1][j],f[i][j-1])+grid[i-1][j-1];

}

}

}

return f[n][m];

}