#include<bits/stdc++.h>
using namespace std;
bitset<1000000000> d(1);
int z2(int n){
	int sum=0;
	int z=1;
	while(n!=0){
		int m=n%2;
		sum=sum+z*m;
		z*=10;
		n/=2;
	}
	return sum;
}
int f(bitset<1000000000> a){
	int ret=0;
	while(a!=0b0){
		ret++;
		a&=a-d;
	}
	return ret;
}
int main(){
	bitset<1000000000> y;
	cin>>y;
	cout<<f(y);
}

_代码19行a&=a-d错了，请问各位大佬该怎么改 _