#include<bits/stdc++.h>
using namespace std;
int main(){
int n,m,sum1=0,sum0=0;
cin>>n>>m;
int arr[n][m];
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
arr[i][j]=getchar();
if(arr[i][j]=='1')
sum1++;
else if(arr[i][j]=='0')
sum0++;
}
}
int ans=min(sum0,sum1);
ans*=2;
cout<<ans;
return 0;
}
还有救吗?