3169.cpp

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<map>
#include<vector>
using namespace std;
typedef long long ll;
#define INF (1LL<<50LL)
int N,M[2];
int A[10001][2],B[10001][2];
ll D[10001][2],d[1111];
ll solve(){
  fill(d,d+1111,INF);
  d[0]=0;
  for(int k=0;k<N;k++){
    for(int i=0;i<N-1;i++)
      if( d[i+1] < INF ) 
	d[i] = min(d[i],d[i+1]);
    for(int j=0;j<2;j++){
      for(int i=0;i<M[j];i++){
	if( d[A[i][j]] < INF )
	  d[B[i][j]]= min( d[B[i][j]], d[A[i][j]] + D[i][j]);
      }
    }
  }
  if(d[0] < 0) {
    return -1;
  } else if( d[N-1]==INF ) {
    return -2;
  }
  return d[N-1];
}

int main(){
  cin >> N >> M[0] >> M[1];
  int a,b,d;
  for(int i=0;i<M[0];i++){
    cin >> a >> b >> d;
    --a; --b;
    A[i][0] = a; B[i][0] = b; D[i][0] = d;
  }
  for(int i=0;i<M[1];i++){
    cin >> a >> b >> d;
    --a; --b;
    A[i][1] = b; B[i][1] = a; D[i][1] = -d;
  }
  cout << solve() << endl;
}