#include <stdio.h>
int main()
{
    int i,j=0,sum=0,a,b=300;
    for(i=0;i<12;i++){scanf("%d\n",&a);
    while(j>=100){j=j-100;sum=sum+100;};
    if(a>b+j){printf("%d",-i-1);break;}
    else{j=j+300-a;};
    }
    while(j>=100){j=j-100;sum=sum+100;}
    int m=sum*1.2+j;
    if(i==12){printf("%d",m);}
    return 0;
}