#include <cstdio>
#include <iostream>
using namespace std;

FILE *in, *out, *score;
long long a[1555],p[1555];

int main(int argc, char * arg [])
{
	in = fopen("podnizovi.in", "r");
	out = fopen("podnizovi.out", "r");
	score = fopen("score.tmp", "w");

	long long n,q,i,l,r,s,wa,imaneg;
	double poeni = 5.0;

	fscanf(in, "%lld%lld", &n, &q);

	p[0] = 0;
	imaneg = 0;
	for(i=1; i<=n; i++) {
        fscanf(out, "%lld", &a[i]);
        p[i] = p[i-1] + a[i];
        if (a[i]<=0) imaneg = 1;
	}

	wa = 0;
	for(i=1; i<=q; i++) {
	    fscanf(in, "%lld%lld%lld", &l, &r, &s);
	    if (p[r] - p[l-1] != s) {
	        wa = 1;
	        //printf("%lld %lld %lld\n", l, r, s);
	    }
	}

	if (wa) {
	    fprintf(score, "0\n");
	    //printf("0\n");
	} else {
	    if (imaneg) {
	        fprintf(score, "%.2lf\n", poeni*0.4);
	        //printf("%.2lf\n", poeni*0.4);
	    } else {
	        fprintf(score, "%.2lf\n", poeni);
	        //printf("%.2lf\n", poeni);
	    }
	}

	fclose(in); fclose(out); fclose(score);

	return 0;
}