#include <cstdio>
#include <cassert>

const int Nmax = 100005;

int N, M, K;
int A[Nmax], B[Nmax];

void ReadData() {
	freopen("stergeri.in", "r", stdin);
	freopen("stergeri.out", "w", stdout);
	
	assert(scanf("%d %d %d", &N, &M, &K) == 3);
	int N2 = N;
	for (int i = 1; i <= M; ++i) {
		assert(scanf("%d %d", A+i, B+i) == 2);
		assert(A[i] <= B[i]);
		assert(1 <= A[i] && B[i] <= N2);
		N2 -= B[i]-A[i]+1;
	}
}

void Solve() {
	for (int i = M; i; --i)
		if (A[i] <= K)
			K += B[i]-A[i]+1;
	printf("%d\n", K);
}

int main() {
	ReadData();
	Solve();
}