week2C

#include<stdio.h>
#include<math.h>

int main()
{
    int n, m, sp[100000][2], i, j, count = 0, a, b, k, p, l=0, ans[50], flag; 
    scanf("%d %d", &n, &m);
    while(m || n)
    {
        for(i=0; i<m; i++)
            scanf("%d %d", &sp[i][0], &sp[i][1]); 
        count = 0;
        for(i=0; i<n; i++)
          for(j=i+1; j<n; j++)
        {
            a = i+1;
            b = j+1;
            for(p=a; p<b; p++)
            {      
                for(k=0; k<m; k++)
                { 
                   if((p==sp[k][0]&&(p+1)==sp[k][1])||((p+1)==sp[k][0]&&p==sp[k][1]))
                   {
                       flag = 1;
                       break;
                   }
               
                   else   
                       flag = 0;       
                }   
            }
            if(flag)
                {
                    count++;
                }
        }
        i = 1;
        for(j=0; j<n; j++)
        {
            i = i%1000000007;
            i *= 2;
        }
        if(m==0)
            ans[l] = i;
        else 
            ans[l] = (i - (2*count)%1000000007 + 1)%1000000007;
        l++;
        scanf("%d %d", &n, &m);
    }
    for(i = 0; i<l; i++)
        printf("%d\n", ans[i]);
}