n,m,k=map(int,input().split());mod=10**9+7
dp=[1]*(n+2);dp[0]=0
x=[list(map(int,input().split())) for i in range(m)]
for i in range(k):
	dp2=[0]*n*2
	for l,r in x:
		c=dp[r]-dp[l-1]+mod;c%=mod
		dp2[l]+=c;dp2[l]%=mod
		dp2[r+1]+=mod-c;dp2[r+1]%=mod
	dp=dp2
	for j in range(1,len(dp)):
		dp[j]+=dp[j-1];dp[j]%=mod
	for j in range(1,len(dp)):
		dp[j]+=dp[j-1];dp[j]%=mod
print((dp[n]-dp[n-1]+mod)%mod)