#include <bits/stdc++.h> using namespace std; #define MAX 0x3f3f3f3f int w[10005],l[10005],F[10005],sum[10005]; int n,t,sw; int Opt(int L,int R) { int W=0,h=0; for(int i=L; i<=R; i++) h=max(l[i],h) ; return sum[R]-sum[L-1]>sw ? MAX : h; } int main() { freopen("book.in","r",stdin); freopen("book.out","w",stdout); scanf("%d%d",&n,&sw); for(int i = 1; i <= n; i++) { scanf("%d%d",&w[i],&l[i]); sum[i]=sum[i-1]+w[i]; } for(int i = 1; i <= n; i++) { F[i] = MAX; for(int j = i-1; j>=0; j--) { if(Opt(j+1,i)>sw) break; F[i]=min(F[i],F[j]+Opt(j+1,i)); } } printf("%d\n",F[n]); return 0; }