#include <bits/stdc++.h>   using namespace std;   long long n, ti[2005], co[2005], dp[2005][2005], i, j;   int main() {     cin >> n;     for (i = 1; i <= n; i++) {       cin >> ti[i] >> co[i];       ti[i]++;     }     for (i = 0; i <= n; i++) {       for (j = 1; j <= n; j++) dp[i][j] = 1e16;     }     for (i = 1; i <= n; i++) {       for (j = 1; j <= n; j++) {         dp[i][j] = min(dp[i - 1][j], dp[i - 1][max(0ll, j - ti[i])] + co[i]);       }     }     cout << dp[n][n];     return 0;   }   