{"raw_statement":[{"iden":"problem statement","content":"It is November $18$ now in Japan. By the way, $11$ and $18$ are adjacent Lucas numbers.\nYou are given an integer $N$. Find the $N$\\-th Lucas number.\nHere, the $i$\\-th Lucas number $L_i$ is defined as follows:\n\n*   $L_0=2$\n*   $L_1=1$\n*   $L_i=L_{i-1}+L_{i-2} (i≥2)$"},{"iden":"constraints","content":"*   $1≤N≤86$\n*   It is guaranteed that the answer is less than $10^{18}$.\n*   $N$ is an integer."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$"},{"iden":"sample input 1","content":"5"},{"iden":"sample output 1","content":"11\n\n*   $L_0=2$\n*   $L_1=1$\n*   $L_2=L_0+L_1=3$\n*   $L_3=L_1+L_2=4$\n*   $L_4=L_2+L_3=7$\n*   $L_5=L_3+L_4=11$\n\nThus, the $5$\\-th Lucas number is $11$."},{"iden":"sample input 2","content":"86"},{"iden":"sample output 2","content":"939587134549734843"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}