MOD = 10 ** 9 + 7

n, m, k = map(int, input().split())

lr = [list(map(int, input().split())) for _ in range(m)]
dp = [0] * (n + 1)
dp[0] = 1
for _ in range(k):
    cum = [0]
    for d in dp[:-1]:
        cum.append(cum[-1] + d)
        if cum[-1] >= MOD:
            cum[-1] -= MOD
    ndp = [0] * (n + 1)
    for l, r in lr:
        plus = (cum[r] - cum[l - 1]) % MOD
        ndp[l - 1] += plus
        ndp[r] -= plus
    for i in range(1, n + 1):
        ndp[i] += ndp[i - 1]
        ndp[i] %= MOD
    dp = ndp
print(dp[n - 1])