1 #include <iostream>
 2 #include <string.h>
 3 using namespace std;
 4 #define MaxSize 1002
 5 int h[MaxSize],hash[MaxSize];
 6 int n,m;
 7 int main(){
 8     //freopen("in.txt","r",stdin);
 9     while (~scanf("%d%d",&n,&m)){
10         int i,j,ans=0;
11         char ch;
12         memset(h,0,sizeof(h));
13         for(i=0;i<n;i++){
14             getchar();
15             memset(hash,0,sizeof(hash));
16             for(j=0;j<m;j++){
17                 ch=getchar();
18                 //scanf("%c",&ch);
19                 if(ch=='1')    h[j]++;
20                 else    h[j]=0;
21                 hash[h[j]]++;
22             }
23             int temp=0;
24             for(j=MaxSize-2;j>0;j--){
25                 hash[j]+=hash[j+1];//每次累积比当前高度大的高度出现次数
26                 temp=hash[j]*j;
27                 ans=ans>temp?ans:temp;
28             }
29         }
30         printf("%d\n",ans);
31     }
32     return 0;
33  }
34