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

dp=[0]*N
dp[0]=1
for t in range(K):
    acc=[0]
    for a in dp:
        acc.append(acc[-1]+a)

    _imos=[0]*(N+1)
    for l,r in data:
        c=acc[r+1]-acc[l]
        _imos[l]+=c
        _imos[r+1]-=c
        _imos[l]%=MOD
        _imos[r+1]%=MOD

    acc=[0]
    for a in _imos:
        acc.append((acc[-1]+a)%MOD)
    dp=acc[1:-1]

print(dp[-1])