1 // 2 //by coolxxx 3 //#include<bits/stdc++.h> 4 #include<iostream> 5 #include<algorithm> 6 #include<string> 7 #include<iomanip> 8 #include<map> 9 #include<stack>10 #include<queue>11 #include<set>12 #include<bitset>13 #include<memory.h>14 #include<time.h>15 #include<stdio.h>16 #include<stdlib.h>17 #include<string.h>18 //#include<stdbool.h>19 #include<math.h>20 #define min(a,b) ((a)<(b)?(a):(b))21 #define max(a,b) ((a)>(b)?(a):(b))22 #define abs(a) ((a)>0?(a):(-(a)))23 #define lowbit(a) (a&(-a))24 #define sqr(a) ((a)*(a))25 #define swap(a,b) ((a)^=(b),(b)^=(a),(a)^=(b))26 #define mem(a,b) memset(a,b,sizeof(a))27 #define eps (1e-8)28 #define J 1029 #define mod 100000000730 #define MAX 0x7f7f7f7f31 #define PI 3.1415926535897932332 #define N 10433 using namespace std;34 typedef long long LL;35 int cas,cass;36 int n,m,lll,ans;37 int a[N],b[N],c[N];38 bool work()39 {40     int i,j,sum=0;41     for(i=1;i<=n;i++)42     {43         sum-=a[i];44         if(sum<0)return 0;45         sum+=b[i];46         if(sum>m)return 0;47         if(c[i]>0 && sum!=m)return 0;48     }49     if(b[n]!=0 || c[n]!=0 || sum!=0)return 0;50     return 1;51 }52 int main()53 {54     #ifndef ONLINE_JUDGE55 //    freopen("1.txt","r",stdin);56 //    freopen("2.txt","w",stdout);57     #endif58     int i,j,k;59 //    for(scanf("%d",&cass);cass;cass--)60 //    for(scanf("%d",&cas),cass=1;cass<=cas;cass++)61 //    while(~scanf("%s",s+1))62     while(~scanf("%d",&m))63     {64         scanf("%d",&n);65         ans=0;66         for(i=1;i<=n;i++)67             scanf("%d%d%d",&a[i],&b[i],&c[i]);68         if(work())puts("possible");69         else puts("impossible");70     }71     return 0;72 }73 /*74 //75 76 //77 */