#include <bits/stdc++.h>
#define read read()
#define up(i,l,r) for(int i = l; i<=r; i++)
using namespace std;int read
{int x = 0; char ch = getchar();while(ch < 48 || ch > 57)  ch = getchar();while(ch >= 48 && ch <= 57) {x = 10 * x + ch - 48; ch = getchar();}return x;
}const int N = 105;int n,m,k;
int sx,sy,ex,ey;
int ans = INT_MAX;
int dx[] = {0,1,-1, 0,0};//上，下，左，右；
int dy[] = {0,0, 0,-1,1};
struct node{int x,y,step;}st;
int th[N][N],vis[N][N];
int nx,ny;void updata(int i,int p)
{if(i==1) (nx += p) > n ?nx = n : nx;     //上else if(i==2) (nx -= p) < 1 ?nx = 1 : nx;//下 else if(i==3) (ny -= p) < 1 ?ny = 1 : ny;//左 else if(i==4) (ny += p) > m ?ny = m : ny;//右
}void bfs()
{queue<node>q;st.step = 0;st.x = sx;st.y = sy;q.push(st);vis[sx][sy]=1;while(!q.empty()){node cur = q.front(); q.pop();if(cur.x == ex && cur.y == ey) {printf("%d",cur.step); exit(0);}up(i,1,4){nx = cur.x + dx[i];ny = cur.y + dy[i];

　　　　　　　if(nx < 1|| ny < 1 || nx > n || ny > m || vis[nx][ny]) continue;vis[nx][ny] = 1;node nxt; nxt.x = nx; nxt.y = ny; nxt.step = cur.step + 1;q.push(nxt);}}printf("Impossible");
}int main()
{freopen("hero2.in","r",stdin);n = read; m = read; k = read;int x,y;int cnt = 0;up(i,1,k){x = read; y = read; th[x][y] = read;}sx = read; sy = read;ex = read; ey = read;bfs();
}

void updata(int i,int p)
{if(i==1) (nx += p) > n ?n : nx;     //上else if(i==2) (nx -= p) < 1 ?1 : nx;//下 else if(i==3) (ny -= p) < 1 ?1 : ny;//左 else if(i==4) (ny += p) > m ?m : ny;//右
}

if(th[nx][ny]) updata(i,th[nx][ny]);