#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);} void reader(double *x){scanf("%lf",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(double x, char c){printf("%.15f",x);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');} char memarr[17000000]; void *mem = memarr; #define MD 1000000007 ll A, B; char buf[1000]; int sz; char arr[100]; ll dp[100][2][2], pt[100][2][2]; void dpp(int d, int las, int fit){ int i, j, k, sd, slas, sfit; ll res = 0; // printf("%d %d %d\n",d,las,fit); if(dp[d][las][fit] >= 0) return; if(d==sz){ dp[d][las][fit] = 0; pt[d][las][fit] = 1; return; } dp[d][las][fit] = pt[d][las][fit] = 0; if(fit){ rep(i,arr[d]+1){ sd = d+1; slas = (i==1?1:0); sfit = (i==arr[d]?1:0); dpp(sd, slas, sfit); dp[d][las][fit] += dp[sd][slas][sfit]; if(las==1 && i==2) dp[d][las][fit] += pt[sd][slas][sfit]; pt[d][las][fit] += pt[sd][slas][sfit]; } } else { rep(i,10){ sd = d+1; slas = (i==1?1:0); sfit = 0; dpp(sd, slas, sfit); dp[d][las][fit] += dp[sd][slas][sfit]; if(las==1 && i==2) dp[d][las][fit] += pt[sd][slas][sfit]; pt[d][las][fit] += pt[sd][slas][sfit]; } } // printf("%d %d %d : %lld %lld\n",d,las,fit,dp[d][las][fit],pt[d][las][fit]); } ll solve(ll n){ int i, j, k; ll res = 0, t; rep(i,20) rep(j,2) rep(k,2) dp[i][j][k] = -1; sprintf(arr, "%lld", n); sz = strlen(arr); rep(i,sz) arr[i] -= '0'; dpp(0, 0, 1); res += dp[0][0][1]; if(sz >= 2){ t = 1; REP(i,2,sz){ res += t; t *= 10; } if(arr[0] > 2){ res += t; } else if(arr[0]==2){ t = 0; REP(i,1,sz) t = t*10 + arr[i]; if(t%10>=2) res += t/10 + 1; else res += t/10; } } return res; } int main(){ int i, j, k; ll res; reader(&A,&B); res = solve(B) - solve(A-1); if((A-1)%10==1){ sprintf(buf,"%lld",A); if(buf[0]=='2') res--; } writerLn(res); return 0; }