#include <stdio.h>
int main(){
    int i,n,j,m[151],d;
    scanf("%d",&n);
    for(i=0;i<n;++i)
        scanf("%d",&m[i]);
    for(i=0;i<n;++i)
        for(j=0;j<n;++j)
            if(m[i]<m[j]){
                d=m[i];
                m[i]=m[j];
                m[j]=d;
            }
    d=0;
    for(i=0;i<n-3;++i)
        if(m[i]==m[i+1])
            if(m[i+1]==m[i+2])
                if(m[i+2]==m[i+3])
                    if(m[i+3]>=600)
                        if(m[i+3]<=700){
            ++d;
            i=i+4;
        }

        printf("%d",d);
        return 0;
}