#include <bits/stdc++.h>
#include <vector>
using namespace std;

int max(int a,int b){
    if(a>b){
        return a;
    }
    return b;
}

int main(){
    int N;
    scanf("%d",&N);
    int a[N];
    for(int i=0;i<N;i++){
        scanf("%d",&a[i]);
        a[i] = a[i] % 10;
    }
    int dp[N][10] = {};
    for(int i=0;i<10;i++){
    	dp[0][i] = -2147483648;
    }
    dp[0][0] = 0;
    dp[0][a[0]] = 1;
    for(int i=1;i<N;i++){
        for(int j=0;j<10;j++){
            dp[i][j] = max(dp[i-1][j],dp[i-1][(10+j-a[i])%10]+1);
        }
    }
    printf("%d",dp[N-1][0]);
}