usaco08oct time management

#include <cstdlib>
#include <algorithm>
#include <cstring>
#include <cctype>
#define INF 2000000000
using namespace std;
typedef long long ll;
int n,t[1005],s[1005],mini=INF;
pair<int,int> P[1005];
bool (int M){
    for(int i=0;i<n;i++){
        if(M+P[i].second<=P[i].first)
            M+=P[i].second;
        else return 0; 
    }
    return 1;
}
void init(){
    scanf("%d",&n);
    for(int i=0;i<n;i++)
        scanf("%d%d",&t[i],&s[i]),
        P[i].first=s[i],P[i].second=t[i],
        mini=min(mini,s[i]);
    sort(P,P+n);
}
void solve(){
    int L=0,R=mini,M;
    while(R-L){
        M=(R+L+1)/2;
        if(judge(M))
            L=M;
        else R=M-1;
    }
    if(!judge(0))L=-1;
    printf("%dn",L);
}
int main(){
    init();
    solve();
    return 0;
}