#include<iostream>
#include<vector>

using namespace std;

int main(){

int N,M,K,a,c=0;

vector<int> V1;
vector<int> V2;

cin >> N >> M >> K;

for(int i = 0; i<N; i++){
    cin >> a;
    V1.push_back(a);
}

for(int i = 0; i<M; i++){
    cin >> a;
    V2.push_back(a);
}

for(int i = 0; i<N; i++){
    for(int j = 0; j<M; j++){
        if(V1[i] - V2[j] <= 5 && V1[i] - V2[j] >= -5){
            c++;
            V2[j] == -50;
            V1[i] == -100;
        }

        }

}

cout << c;

}