#include <stdio.h>
#include <algorithm>
#include<iomanip>

#define MAX 1e9
#define MAXN 1002
#define MAXG 10002

int N, G, Pmax;
int W[MAXN], P[MAXN];
int D[2][MAXG];

int main(){
    freopen("energii.in", "r", stdin);
    freopen("energii.out", "w", stdout);

    scanf("%d%d", &N, &G);
    for(int i = 1; i <= N; ++i)
        scanf("%d%d", &W[i], &P[i]);

    for(int i = 0; i <= N; ++i)
        for(int cw = 0; cw <= G; ++cw)
            D[i][cw] = MAX;

    for(int i = 1; i <= N; ++i)
        for(int cw = G; cw <= G; ++cw){
            D[i][cw] = D[i - 1][cw];

            if(W[i] <= cw)
                D[i][cw] = std::min(D[i][cw], D[i][cw - W[i]] + P[i]);
            else
                D[i][cw] = std::min(D[i][cw], P[i]);
        }

    if(D[N][G] == 1e9)
        printf("-1");
    else
        printf("%d", Pmax);
    return 0;
}