#include<bits/stdc++.h>
using namespace std;
int main(){
//ios_base::sync_with_stdio(false);
int counts, n, m, s[1000001], a[1000001];
cin >> n >> m;
for(int i=0; i<n; i++){cin >> s[i];}
for(int i=0; i<m; i++){cin >> a[i];}
for(int i=1; i<m; i++){
a[i]-=a[0];
}
a[0]=0;
bool found;
counts =0;
for(int i=0; i<=(n-m); i++){
found=true;
for(int j=i+1; j<i+m; j++){
if((s[j]-s[i])!=a[j-i]){found=false;break;}
}
if(found){counts++;}
}
cout << counts;
return 0;
}
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