module Main;

import BinaryHeap;
import BoolArray;
import CPLib.Arithmetic;
import CPLib.DSegtree;
import CPLib.Graph;
import CPLib.IO;
import CPLib.LSegtree;
import CPLib.UnionFind;
import CPLib.ZP;
import CPLib.Monoid;
import HashMap;
import HashSet;

type Z = ZP P1000000007;

// type Tree = 
type Tree = LSegtree (WeightedSum Z) (RangeAdd WeightedSum Z);

main : IO () = (
    let cN = *read_i; // 回数
    let cM = *read_i; // エレベータの数
    let cK = *read_i; // 移動回数
    let cLRs = *range(0, cM).fold_m([], |_, cLRs|
        let l = *read_i;
        let r = *read_i;
        let l = l - 1;
        cLRs.push_back((l, r)).pure
    );
    let t = LSegtree::create(cN) : Tree;
    let t = t.set(0, WeightedSum::make_single(zp(1)));
    let s = LSegtree::build(fill(cN, make_single(zp(0)))) : Tree;    
    let (t, _) = range(0, cK).fold((t, s), |k, (t, s)|
        let s = range(0, cN).fold(s, |n, s| s.set(n, make_single(zp(0))));
        let s = range(0, cM).fold(s, |m, s|
            let (l, r) = cLRs.@(m);
            let sum = t.fold(l, r);
            let s = s.act_range(l, r, RangeAdd { a : sum.@v });
            s
        );
        (s, t)
    );
    let ans = t.@(cN-1);
    ans.@v.@value.to_string.println
);