ural 1880. Psych Up's Eigenvalues

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
int num[3][4005];

int sav[4005];
int top=0;

int main(){
//    freopen("data.txt","r",stdin);
    int n[3];
    scanf("%d",&n[0]);
    for(int i=0;i<n[0];++i)
    {
        scanf("%d",&num[0][i]);
    }
    scanf("%d",&n[1]);
    int it=0;
    for(int i=0;i<n[1];++i)
    {
        scanf("%d",&num[1][i]);
        for(;it<n[0];++it)
        {
            if(num[0][it]==num[1][i]){sav[top++]=num[1][i];break;}
            if(num[0][it]>num[1][i])break;
        }
    }
    scanf("%d",&n[2]);
    int ans=0;
    it=0;
    for(int i=0;i<n[2];++i)
    {
        scanf("%d",&num[2][i]);
        for(;it<top;++it)
        {
            if(sav[it]==num[2][i]){
                ans++;break;
            }
            if(sav[it]>num[2][i])break;
        }
    }
    printf("%d\n",ans);
    return 0;
}