N, M, K = map(int, input().split())
data = [list(map(int, input().split())) for _ in range(M)]

MOD = 10**9 + 7
dp = [0] + [1]*N

for _ in range(K):
    nex = [0] * (N+1)
    for li, ri in data:
        si = dp[ri] - dp[li-1]
        nex[li] += si
        nex[li] %= MOD
        if ri < N:
            nex[ri+1] -= si
            nex[ri+1] %= MOD
    
    for i in range(1, N+1):
        nex[i] += nex[i-1]
        nex[i] %= MOD
    
    for i in range(1, N+1):
        nex[i] += nex[i-1]
        nex[i] %= MOD
    
    dp = nex

print(dp[N] - dp[N-1])