#include<bits/stdc++.h>
using namespace std;

int main(){
int n, p;
cin >> n >> p;
bool passed[1005];
for (int i = 0; i < n; ++i) {
    int pid, state;
    cin >> pid >> state;
    if (state == 1 && !passed[pid]) {
        passed[pid] = true;
    }
}
int count_passed = 0;
for (int i = 1; i <= p; ++i) {
    if (passed[i]) count_passed++;
}
cout << count_passed << endl;
	return 0;
}

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