N, M, K = map(int, input().split())
LR = []
for i in range(M):
    l, r = map(int, input().split())
    LR.append([l - 1, r])
MOD = 10 ** 9 + 7

dp1 = [0] * (N + 1)
dp2 = [0] * (N + 1)
dp1[0] = 1

for i in range(K):
    sum0 = [0] * (N + 1)
    for j in range(N):
        sum0[j + 1] = (sum0[j] + dp1[j]) % MOD
    for l, r in LR:
        add0 = (sum0[r] - sum0[l]) % MOD
        dp2[l] = (dp2[l] + add0) % MOD
        dp2[r] = (dp2[r] - add0) % MOD
    for j in range(N):
        dp2[j + 1] = (dp2[j + 1] + dp2[j]) % MOD

    dp1, dp2 = dp2, dp1
    dp2 = [0] * (N + 1)

print(dp1[N - 1])