Saving HDU

#include
using namespace std;
struct bao{int pi, mi;
}a[100], b;
void quick_sort(bao s[], int l, int r){if(l < r){int i=l, j=r, x=s[l].pi;b = s[l];while(i < j){while(i < j && s[j].pi >= x)  j--;if(i < j)  s[i++] = s[j];while(i < j && s[i].pi < x)  i++;if(i < j)  s[j--] = s[i];}s[i] = b;quick_sort(s, l, i-1);quick_sort(s, i+1, r);}
}
int main(){int v, n;while(cin>>v, v){cin>>n;int i, sum;for(i=0; i>a[i].pi>>a[i].mi;quick_sort(a, 0, n-1);i=n-1, sum=0;while(v>0 && i>=0){if(v-a[i].mi> 0){sum += a[i].pi * a[i].mi;v -= a[i].mi;i--;}else {sum += v * a[i].pi ;break;}}cout<