#include using namespace std; #define REP(i,a,b) for(i=a;i'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);} void reader(ll *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);} int reader(char c[]){int i,s=0;for(;;){mygc(i);if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF) break;}c[s++]=i;for(;;){mygc(i);if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF) break;c[s++]=i;}c[s]='\0';return s;} template void reader(T *x, S *y){reader(x);reader(y);} template void reader(T *x, S *y, U *z){reader(x);reader(y);reader(z);} template void reader(T *x, S *y, U *z, V *w){reader(x);reader(y);reader(z);reader(w);} void writer(int x, char c){int s=0,m=0;char f[10];if(x<0)m=1,x=-x;while(x)f[s++]=x%10,x/=10;if(!s)f[s++]=0;if(m)mypc('-');while(s--)mypc(f[s]+'0');mypc(c);} void writer(ll x, char c){int s=0,m=0;char f[20];if(x<0)m=1,x=-x;while(x)f[s++]=x%10,x/=10;if(!s)f[s++]=0;if(m)mypc('-');while(s--)mypc(f[s]+'0');mypc(c);} void writer(const char c[]){int i;for(i=0;c[i]!='\0';i++)mypc(c[i]);} void writer(const char x[], char c){int i;for(i=0;x[i]!='\0';i++)mypc(x[i]);mypc(c);} template void writerLn(T x){writer(x,'\n');} template void writerLn(T x, S y){writer(x,' ');writer(y,'\n');} template void writerLn(T x, S y, U z){writer(x,' ');writer(y,' ');writer(z,'\n');} template void writerArr(T x[], int n){int i;if(!n){mypc('\n');return;}rep(i,n-1)writer(x[i],' ');writer(x[n-1],'\n');} #define MD 1000000007 int X, Y; int M[111][111]; int q[2222222], q_st, q_size; int dist[2222222]; int isK(int a, int b , int c){ if(!a || !b || !c) return 1; if(a==c) return 0; if(a < b && b > c) return 1; if(a > b && b < c) return 1; return 0; } struct dimensionCompress2 { int B; void set(int b){B=b;} void set(int a, int b){B=b;} int mask(int a, int b){return a*B+b;} void para(int mask, int *a, int *b){*a=mask/B;*b=mask%B;} }; struct dimensionCompress3 { int B, C; void set(int b, int c){B=b;C=c;} void set(int a, int b, int c){B=b;C=c;} int mask(int a, int b, int c){return(a*B+b)*C+c;} void para(int mask, int *a, int *b, int *c){*a=mask/(B*C);*b=mask%(B*C)/C;*c=mask%C;} }; struct dimensionCompress4 { int B, C, D; void set(int b, int c, int d){B=b;C=c;D=d;} void set(int a, int b, int c, int d){B=b;C=c;D=d;} int mask(int a, int b, int c, int d){return((a*B+b)*C+c)*D+d;} void para(int mask, int *a, int *b, int *c, int *d){*a=mask/(B*C*D);*b=mask%(B*C*D)/(C*D);*c=mask%(C*D)/D;*d=mask%D;} }; struct dimensionCompress5 { int B, C, D, E; void set(int b, int c, int d, int e){B=b;C=c;D=d;E=e;} void set(int a, int b, int c, int d, int e){B=b;C=c;D=d;E=e;} int mask(int a, int b, int c, int d, int e){return(((a*B+b)*C+c)*D+d)*E+e;} void para(int mask, int *a, int *b, int *c, int *d, int *e){*a=mask/(B*C*D*E);*b=mask%(B*C*D*E)/(C*D*E);*c=mask%(C*D*E)/(D*E);*d=mask%(D*E)/E;*e=mask%E;} }; int main(){ int i, j, k, a, b, d; int mask, nmask; int res = -1; int dx[4] = {-1,1,0,0}, dy[4] = {0,0,-1,1}; int ni, nj; dimensionCompress3 coo; reader(&Y,&X); rep(i,X) rep(j,Y) reader(M[i]+j); coo.set(10, X, Y); rep(i,10*X*Y) dist[i] = -1; dist[0] = 0; q_st = q_size = 0; q[q_st+q_size++] = 0; while(q_size){ mask = q[q_st++]; q_size--; coo.para(mask, &k, &i, &j); if(i==X-1 && j==Y-1){ res = dist[mask]; break; } rep(d,4){ ni = i + dx[d]; nj = j + dy[d]; if(ni < 0 || nj < 0 || ni >= X || nj >= Y) continue; if(!isK(k,M[i][j],M[ni][nj])) continue; nmask = coo.mask(M[i][j], ni, nj); if(dist[nmask] >= 0) continue; dist[nmask] = dist[mask] + 1; q[q_st+q_size++] = nmask; } } writerLn(res); return 0; }