#include<iostream> #include<cstring> using namespace std; int main() { int u,v,w[1005]={0},x[1005]={0},y[1005]={0},len1,len2,len3,z,s; cin>>u>>v; w[1]=1; x[1]=1; len1=1; len2=1; for(z=3;z<=v-u+1;z++) { s=0; len3=1; while(len3<=len1||len3<=len2) { y[len3]=w[len3]+x[len3]+s; s=y[len3]/10; y[len3]%=10; len3++; } for(int i=1;i<=len2;i++) w[i]=x[i]; for(int i=1;i<=len3;i++) x[i]=y[i]; len1=len2; len2=len3; } if(v-u<=2) cout<<1; else { y[len3]=s; while(y[len3]==0&&len3>1) len3--; for(int i=len3;i>=1;i--) cout<<y[i]; } return 0; }