#include<cstdio>
#include<cstring>
int n,i,A[210],B[210],C[210],t;
int main() {
    freopen("nunta.in","r",stdin),freopen("nunta.out","w",stdout),scanf("%hd",&n);
    A[0]=B[0]=C[0]=A[1]=B[1]=C[1]=1;
    for(;n>1;n--) {
        for(t=0,i=1;i<=A[0]||i<=B[0]||t;i++)
            t+=A[i]+B[i],C[i]=t%10,t/=10;
        C[0]=i-1,memcpy(A,B,sizeof(B)),memcpy(B,C,sizeof(C));
    }
    for(i=C[0];i;i--)
        printf("%hd",C[i]);
}