bool M1;
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define ull unsigned long long
#define LL __int128
#define db double
#define LD long double
#define Pii pair<int,int>
#define Pll pair<ll,ll>
#define Pull pair<ull,ull>
#define Pdb pair<db,db>
#define fir first
#define sec second
#define vec vector<int>
#define pb push_back
#define qlr cerr<<"qlr\n"
#define dyh cerr<<"dyh\n"
#define pc(x) __builtin_popcount(x)
#define uni(x,y) uniform_int_distribution<int>(x,y)(rng)
#define unl(x,y) uniform_int_distribution<ll>(x,y)(rng)
#define unr(x,y) uniform_real_distribution<double>(x,y)(rng)
#define F(i,a,b) for(int i=a,i##end=b;i<=i##end;i++)
#define UF(i,a,b) for(int i=a,i##end=b;i>=i##end;i--)
#define look_memory cerr<<'\n'<<abs(&M1-&M2)/1024.0/1024<<'\n'
#define look_time cerr<<'\n'<<clock()*1.0/CLOCKS_PER_SEC<<'\n'
mt19937 rng(time(0)^(*new int));
const int INF=0x3f3f3f3f;
const int Mod=998244353;
template<typename T>
inline void inc(T &a,T b){
	if(b<0) b+=Mod;
	a+=b;
	if(a>=Mod) a-=Mod;
}
template<typename T>
inline void dec(T &a,T b){
	if(b<0) b+=Mod;
	a-=b;
	if(a<0) a+=Mod;
}
template<typename T>
inline void muc(T &a,T b){
	a=a*b%Mod;
}
template<typename T>
inline bool chkmin(T &a,T b){
	if(a<=b) return false;
	a=b;
	return true;
}
template<typename T>
inline bool chkmax(T &a,T b){
	if(a>=b) return false;
	a=b;
	return true;
}
ll n,A,B,tot,ans;
ll ant[50010];
bool vis[50010];
Pll a[50010];
vector<ll> t[50010],g[100010];
gp_hash_table<ll,int> mp,id;
struct Edge{
    ll u,v,w,ty;
};
Edge b[1000010];
struct Dsu{
    #define N 200000
    int fa[N+10];
    void init(int n){
        F(i,0,n) fa[i]=i;
    }
    int fd(int x){
        return fa[x]==x?x:fa[x]=fd(fa[x]);
    }
    void merge(int x,int y){
        x=fd(x),y=fd(y);
        fa[x]=y;
    }
    #undef N
}dsu;
ll query1(ll x,vector<Pll> V){
    vis[V[0].sec]=1;
    if(V[0].fir>=x) return x;
    if((int)V.size()==1) return V[0].fir;
    ll t1=V[0].fir,t2=min(V[1].fir,x)/t1*t1;
    F(i,1,V.size()-1) V[i].fir-=t2;
    x-=t2;
    V.insert(lower_bound(V.begin()+1,V.end(),V[0]),V[0]);
    V.erase(V.begin());
    reverse(V.begin(),V.end());
    while(!V.empty()&&!V.back().fir) V.pop_back();
    reverse(V.begin(),V.end());
    return query1(x,V)+max(t1-x,0ll);
}
void query2(ll x,vector<ll> &V1,vector<ll> &V2){
    if(V1[0]>=x||(int)V1.size()==1){
        for(auto &i:V2) if(i>0) i%=V1[0];
        mp.clear();
        F(i,0,V2.size()-1){
            if(V2[i]<0) continue;
            if(mp.find(V2[i])!=mp.end()) dsu.merge(i,mp[V2[i]]);
            else mp[V2[i]]=i;
        }
        return;
    }
    ll t1=V1[0],t2=min(V1[1],x)/t1*t1;
    F(i,1,V1.size()-1) V1[i]-=t2;
    V1.insert(lower_bound(V1.begin()+1,V1.end(),V1[0]),V1[0]);
    V1.erase(V1.begin());
    reverse(V1.begin(),V1.end());
    while(!V1.empty()&&!V1.back()) V1.pop_back();
    reverse(V1.begin(),V1.end());
    x-=t2;
    if(x<t1){
        for(auto &i:V2) if(i>0) i=max(i-t2+t1,(i-1)%t1+1);
        mp.clear();
        F(i,0,V2.size()-1){
            if(V2[i]<0) continue;
            if(V2[i]<=x) V2[i]=V2[i];
            else if(V2[i]>t1) V2[i]-=t1;
            else{
                if(mp.find(V2[i])!=mp.end()) dsu.merge(i,mp[V2[i]]);
                else mp[V2[i]]=i;
                V2[i]=-1;
            }
        }
    }
    else for(auto &i:V2) if(i>0) i=max(i-t2,(i-1)%t1+1);
    bool fl=0;
    for(auto i:V2) if(i>0) fl=1;
    if(fl) query2(x,V1,V2);
}
void solve(int L,int R,vector<ll> V){
    if((int)V.size()<=1) return;
    while(L<R&&ant[R]==ant[R-1]) R--;
    if(L==R){
        if(L!=A+1) F(i,1,V.size()-1) b[++B]={V[i-1],V[i],a[L].sec,2};
        return;
    }
    int mid=(L+R)>>1;
    dsu.init(V.size()-1);
    vector<ll> f,V1,V2;
    
    V1=t[mid],V2=V;
    query2(n,V1,V2);
    V1.clear(),V2.clear();
    
    F(i,0,V.size()-1) f.pb(dsu.fd(i));
    F(i,0,V.size()-1) V1.pb(i);
    sort(V1.begin(),V1.end(),[&](ll cm1,ll cm2){return f[cm1]<f[cm2];});
    for(int i=0,j=0;i<(int)V1.size();i=j+1){
        j=i;
        while(j<(int)V1.size()-1&&f[V1[j+1]]==f[V1[i]]) j++;
        V2.clear();
        F(k,i,j) V2.pb(V[V1[k]]);
        solve(L,mid,V2);
    }
    V2.clear();
    F(i,0,V.size()-1) if(f[i]==i) V2.pb(V[i]);
    solve(mid+1,R,V2);
}
bool M2;
int main(){
	freopen("mst.in","r",stdin);
	freopen("mst.out","w",stdout);
	srand(time(0)^(*new int));
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
    cin>>n>>A>>B;
    F(i,1,A) cin>>a[i].fir>>a[i].sec;
    F(i,1,B) cin>>b[i].u>>b[i].v>>b[i].w;
    F(i,1,B) b[i].u++,b[i].v++,b[i].ty=1;
    sort(a+1,a+A+1,[&](Pll cm1,Pll cm2){return cm1.sec<cm2.sec;});
    vector<Pll> V,tV;
    F(i,1,A){
        V.pb({a[i].fir,0});
        sort(V.begin(),V.end());
        F(j,0,V.size()-1) V[j].sec=j;
        F(j,0,V.size()-1) vis[j]=0;
        ant[i]=(n-query1(n,V))%Mod;
        tV.clear();
        F(j,0,V.size()-1) if(vis[j]) tV.pb(V[j]);
        V=tV;
        for(auto j:V) t[i].pb(j.fir);
    }
    F(i,1,A) ans=(ans+(ant[i]-ant[i-1])*a[i].sec)%Mod;

    vector<ll> rf;
    F(i,1,B) rf.pb(b[i].u),rf.pb(b[i].v);
    sort(rf.begin(),rf.end());
    rf.erase(unique(rf.begin(),rf.end()),rf.end());
    F(i,0,rf.size()-1) id[rf[i]]=i;

//	dsu.init(1);
//	query2(n,{8,11},{15,17});
//	F(i,0,1) cout<<dsu.fd(i)<<' ';

    solve(1,A+1,rf);

    sort(b+1,b+B+1,[&](Edge cm1,Edge cm2){return cm1.w<cm2.w;});
    
    dsu.init(rf.size()-1);
    F(i,1,B){
        if(b[i].ty==1) continue;
        ll u=id[b[i].u],v=id[b[i].v],w=b[i].w;
        if(dsu.fd(u)==dsu.fd(v)) continue;
        dsu.merge(u,v);
        dec(ans,w);
    }
    dsu.init(rf.size()-1);
    F(i,1,B){
        ll u=id[b[i].u],v=id[b[i].v],w=b[i].w;
        if(dsu.fd(u)==dsu.fd(v)) continue;
        dsu.merge(u,v);
        inc(ans,w);
    }
    ans=(ans%Mod+Mod)%Mod;
    cout<<ans;
	look_memory;
	look_time;
	return 0;
}
/*
g++ D2.cpp -o D2 -std=c++14 -O2&&./D2

20 3 2
11 2
8 0
19 0
14 0 3
12 16 1

*/