N, M, K = map(int, input().split())
elv = [tuple(map(int, input().split())) for _ in range(M)]
MOD = 10 ** 9 + 7

dp = [0] * (N + 2)
dp[1] = 1


def accumulate_mod(X):
    res = [0] * len(X)
    res[0] = X[0]
    for i in range(1, len(X)):
        res[i] = (res[i - 1] + X[i]) % MOD
    return res


for _ in range(K):
    acc = accumulate_mod(dp)
    imos = [0] * (N + 2)
    for l, r in elv:
        s = acc[r] - acc[l - 1]
        imos[l] += s
        imos[r + 1] -= s
    dp = accumulate_mod(imos)
print(dp[N])