斜二进制数

#include<iostream>
#include<string>
#include<stdio.h>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include <math.h>

using namespace std;

char a[1005];

int main(){
    scanf("%s",a);
    int len = strlen(a);
    long long sum = 0;
    for(int i = 0 ; i < len ; i++)
    {
        sum += (a[i] -'0') * ( pow(2,len - i) -1);
    //    cout<<sum<<endl;
    }
    if(2147483647 < sum)
        cout<<"too long!"<<endl;
    else
        printf("%d\n",sum);
    //printf("%s\n",a);
    return 0;
}