bitop

/*
 Author: 曹北健(37509)
 Result: AC Submission_id: 4267578
 Created at: Sat Apr 02 2022 11:50:25 GMT+0800 (China Standard Time)
 Problem: 5455  Time: 4 Memory: 1736
*/

#include <stdio.h>
int main(){
char buffer[100] = { 0 };
    scanf("%s", buffer);
    int n = strlen(buffer), i;
    unsigned long long ans = 0, p = 0;
    for(i = n - 1; i >= 0; i--){
        ans |= ((unsigned long long)(buffer[i] - '0') << (unsigned long long )p);
        p++;
    }
    printf("%llu\n", ans);
return 0;
}