#include <bits/stdc++.h>
using namespace std;
int main() {
long long n, m;
cin >> n >> m;
long long a[n];
for (int i = 0; i < n; i++) {
cin >> a[i];
}
long long b[m];
for (int j = 0; j < m; j++) {
cin >> b[j];
}
sort(a, a + n);
sort(b, b + m);
int i = 0;
int j = 0;
int dem = 0;
while (i < n && j < m) {
if (a[i] > b[j]) {
dem++;
i++;
j++;
} else {
i++;
}
}
cout << dem;
return 0;
}
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