diff --git a/cli/src/assets/program/main.rs b/cli/src/assets/program/main.rs
index 0947d086ac..d6c371960c 100644
--- a/cli/src/assets/program/main.rs
+++ b/cli/src/assets/program/main.rs
@@ -5,7 +5,7 @@ extern crate succinct_zkvm;
 succinct_zkvm::entrypoint!(main);
 
 pub fn main() {
-    let n = 10;
+    let n = succinct_zkvm::io::read::<u32>();
     let mut a = 0;
     let mut b = 1;
     let mut sum;
@@ -14,5 +14,7 @@ pub fn main() {
         a = b;
         b = sum;
     }
-    println!("b: {}", b);
+
+    succinct_zkvm::io::write(&a);
+    succinct_zkvm::io::write(&b);
 }
diff --git a/cli/src/assets/script/main.rs b/cli/src/assets/script/main.rs
index 8a60c7b023..e120ab0fbb 100644
--- a/cli/src/assets/script/main.rs
+++ b/cli/src/assets/script/main.rs
@@ -1,12 +1,28 @@
 //! A simple script to generate and verify the proof of a given program.
 
-use succinct_core::{utils, SuccinctProver};
+use succinct_core::{SuccinctProver, SuccinctStdin, SuccinctVerifier};
 
 const ELF: &[u8] = include_bytes!("../../program/elf/riscv32im-succinct-zkvm-elf");
 
 fn main() {
-    std::env::set_var("RUST_LOG", "info");
-    utils::setup_logger();
-    let prover = SuccinctProver::new();
-    prover.run_and_prove(ELF);
+    // Generate proof.
+    let mut stdin = SuccinctStdin::new();
+    stdin.write(&5000u32);
+    let mut proof = SuccinctProver::prove(ELF, stdin).expect("proving failed");
+
+    // Read output.
+    let a = proof.stdout.read::<u32>();
+    let b = proof.stdout.read::<u32>();
+    println!("a: {}", a);
+    println!("b: {}", b);
+
+    // Verify proof.
+    SuccinctVerifier::verify(ELF, &proof).expect("verification failed");
+
+    // Save proof.
+    proof
+        .save("proof-with-pis.json")
+        .expect("saving proof failed");
+
+    println!("succesfully generated and verified proof for the program!")
 }
diff --git a/core/src/lib.rs b/core/src/lib.rs
index ac984984a6..56b0566d5d 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -33,7 +33,6 @@ pub mod utils;
 pub use io::*;
 
 use anyhow::Result;
-use rand::{rngs::StdRng, SeedableRng};
 use runtime::{Program, Runtime};
 use serde::Serialize;
 use stark::{ProgramVerificationError, Proof};